I have been searching this forum and the rest of the internet how to do this, but I cannot seem to find it. So maybe it is not even possible:

I have created a few drum kits from own samples. When I browse through the drumkits I can hear previews for all factory kits and kits from packs but my own drumkits don't have a preview.Can I (and if so, how?) add previews for my own drumkits so that I can audition them when scrolling through the list?

I don't like the .alc aproach for this particular use case because it always comes with a midi clip attached and most of the time I want to start fresh so I'd have to remove the midi clip which is an extra click or two. So I understand there is currently no way to add a preview to a sound like the ableton instruments do... unfortunate...

I've always been pretty sure that's it's absolutely doable by replicating the folders' hierarchy, compressing your preview using the same codec etc... But I've never tried because it'd pretty laborious anyway. I use midi clips, or audio bounces to make my own previews.